Abstract Background In 2006 the Royal College of Surgeons in Ireland, (RCSI), introduced the first four year Graduate Entry Programme (GEP) in medicine in Ireland in line with national policy to broaden access to medical education. One concern considered at the time, was whether the GEP students could be trained to the same standard as their undergraduate Direct Entry Programme (DEP, five/six year duration) counterparts in the shorter time frame. Since students from both cohorts undertake the same examinations in the final two years, it is possible to directly compare GEP vs DEP outcomes. The primary aim of the current study was to analyse the comparative performance of GEP and DEP students undergoing these examinations between 2008 and 2013. Methods Scores from five assessments performed during the final two years were transformed to z scores for each student and 4 scores for the penultimate year were summed to create a unit weighted composite score. The resultant scores for each of the two years were used to assess the comparative performance of GEP vs DEP cohorts and to perform sub-cohort analyses of GEP outcomes. Results In all cohorts/years examined, evidence demonstrated significantly better assessment outcomes for the GEP group for the final two years’ examinations as compared with the DEP group. In all but one cohort examined, this advantage was retained when nationality factors were excluded. Further analyses showed no difference in outcomes between GEP students having science vs. non-science backgrounds and/or between those from EU vs non-EU backgrounds. Finally, data suggested weak correlations between total composite scores and entry scores in American (r = 0.15) and Australian (r = 0.08) medical school admissions tests. Conclusions We have shown for the first time in Ireland, that graduate-entry students perform at least as well, or even better, than a corresponding undergraduate-entry group. Moreover, having a scientific background on entry to the GEP confers no advantage in final assessments. These data provide evidence of the viability of the graduate entry route into medical education in Ireland.